Show TEST OF IGNITION SYSTEM IS IMPORTANT IN LOCATING GASOLINE ENGINE TROUBLE I From the United States Department of o oi s' s i Agriculture With all engines engine using spark plugs It Is comparatively easy to ascertaIn whether the ignition system Is workIng workIng work work- Ing properly Simply remove a n plug and ascertain that the Ole porcelain or 01 other Insulating material on the Inside of at the plug Is not coated with carbon and that the points are arc properly I spaced One thirty-second thirty of oC an Inch Is about the thc right space for Cor most SS S'S systems terns where n a dry battery Is used This is about equal to the thickness of a worn dime A wider gap will often make starting difficult especially wh when u uthe the spark Is rather weak or 01 where a high tension magneto Is used In tI the e latter case the best results will often be obtained when the gap Is not more than one-fortieth one or even one fiftieth of or an Inch Then re-attach re the wire and lay a the plug so so that the metal I base touches the engine casting while the end of the wire and the metal tip of the plug are at least half n an nn anInch Inch from any metal part connected with the engine and In such a n position position position tion that the points are visible while cranking the engine Then turn the engine over a few times at least as many times as ns there are c cylinders and note whether a spark jumps across the he space between the points It Is not sufficient however merely to ascertain ascertain ascertain as as- certain If It there Is a n spark spark spark-It It must be hot enough to fire the compressed the cylinder It is of course difficult to 10 tell by merely looking looking-at nt It whether hethel the spark is hot enough or not but If It is a heavy blue or a n white bluish or a fat yellow one I looking like a small flame it Is probably probably probably ably all right If ver very thin and greenIsh greenish greenish green green- ish or showing red the chances are It Is too weak to fire the charge One Onema ma may familiarize himself with the aspect aspect aspect as as- of a good spark as follows Finding a Good Spark While the motor Is In satisfactory running condition loosen the nut on the top of the plug while the engine Is stopped so It will be easy to remove the wire from the plug after the engine engine engine en en- gine gine- Is started Then start the engine engine engine en en- gine and by taking hold of the wire where It Is covered with insulation move the end of the wire e very sl slowly away from the th center of the plug and watch the spark jump closely observIng observing observing ing Its color and thickness Jt Tt is also well to note the distance the spark will jump yet not advisable to o force It Jt to jump too great reat a 1 gap gnp nor nor should the end of the wire be allowed al aI- al- al I towed owed to rest In a position where the spark cannot jump to the plug or the engine while the engine is running as ast t this ls tends ends to break down the Insulation Insulation insulation tion of the coil coU In the case of high- high tension magnetos there Is no danger danger- 1 fp p this respect as they are fitted with witha a a u safety spark iq rk gap which the spark will jump If for any reason the circuit Is broken elsewhere j Knowledge of just how much of a spark one should obtain with each kind of Ignition system Is frequently I of great value in locating trouble and everyone who operates a gas engine should make the described above-described tests while the engine Is In good order If one Is not sufficiently familiar with the looks of a good spark to tell by mere observation whether It Is hot bot enough a rough test may be made as follows Place a n thin piece of at dry cardboard such as an nn ordinary visIting visiting visiting vis vis- card or three or orr four x fry newspaper between between the the points C Jl the plug while It Is lying Ing on the engine In the position first mentioned then crank the engine A good spark will jump through these leaving a tiny hole A spark which will not do tills this Is too weak to jump the spark gap In the cylinder under compres compres- sion slon If the engine Is equipped with a make break Ignition system In which an Igniter block is used Instead of a spark plug It can be ascertained easily whether the entire system with the exception of the Igniter block Is In good shape by disconnecting the wire from the Igniter block and snapping snapping snap snap- ping It across the corner cornet of at the engine engine engine en en- gine casting or the end of the other wire leading from the coil colI But even though this gives n a good spark It does not necessarily mean menn that the spark Is given glyen In the cylinder when the engine Js is t turned over oyer It may maybe maybe be bc that the points of the electrodes Inside the c cylinder lInder do not touch each ench other when thc they should or are arc not making a good contact because carbon carbon carbon car car- bon Girt dirt frt etc have accumulated between these points Therefore If It Ifa Ita ifa a good spark sparl occurs when the wire Is 18 snapped across part of ot the engine crank the engine until the movable electrode Is released and allowed to fly back Contact Not Being Made If one Is not sure Just when tho the points of the electrode should be touchIng touchIng touch touch- Ing the engine may be cranked very slowly for two full revolutions while the end of the wire Is repeatedly snapped across Its connection on the electrode If no spark sparl can be obtained obtained obtained ob ob- at an any position of the electrode It t Is evident that contact Is not being made b by the points inside the cylinder cylinder der this Is In case the other wire is grounded directly to the engine Sometimes the other wire Is fastened to a piece of metal insulated from Crom the engine but which touches part pmt of oC the engine for an instant when the spark should occur In the time cylinder cUnder In this case if a spark can be obtained by bringing the ends of the two wires into contact should It-should It be determined Ined whether er the insulated piece Is m making contact contact contact con con- tact with the engine properly If no spark is obtained at the plug or Igniter block when tested as ns di directed directed directed di- di It will of course be sary to look over ovel the electrical system In order to ascertain what Is wrong The electrical systems of various engines engines engines en en- gines differ durer considerably and no definite definite definite nite Instruction can be given for different different different dif dif- ferent makes but some general points will be mentioned First of all nil see that the switch is in starting position Much time lime has been lost in thousands of cases by trying to start the engine engine en en- gine with the switch off ott Next Nest look over all wire connections to see that they are tight and clean clean If f the engine starts on a battery of dr dry cells see that all connections between between be be- tween the cells are tight and that no short circuits are caused by the metallic metallic me me- portions of the cells touching with other or by metal connection with the time engine or by tools lying on the cells etc The small knurled nuts on ondry ondry dry cells cell frequently loosen from vibration vibration vi vi- bration and thus Interrupt the whole Ignition s system i Testing Battery Strength It t Is a good thing to keep leep an ammeter ammeter ammeter am am- meter handy for tor use In testing the strength of the cells of a battery In testing with an ammeter It is best to discard all cells that do not test over 12 12 amperes A new cell should test between 20 and 30 amperes If no no ammeter Is available a crude test can be made by striking the end of a n wire connected to one end cell of the bat battery batterr battery bat bat- tery terr against the first connection on the cell at the time other end Do not keep the wire In contact with the cell for tor more than an nn instant in In- stant Doing so will weaken the battery battery battery bat bat- tery but by snapping It quickly across the edge edgo of of the knurled nut a few times and n noting Ung the sparks one can ascertain whether the battery Is producing producing producing pro pro- a good current By making this test a few times with a 0 battery which Is In working condition one can easily learn about how much of a spark should be expected OH Oil Causes Trouble Sometimes too much oil all will cause came e trouble by accumulating on the contact contact contact con con- tact points In the breaker box It Is usually easy easto to examine these points and see if they have oil all on them are rough or pitted or not opening proper prop prop- er erly If olI oily rinse with a little gasoline gasoline gasoline gas gas- oline and wipe dry |